NLCD 2001, grid cells (30m x 30m) contained within the basin classified as low, medium, or high intensity urban development (land-cover classes 22, 23, 24), and dividing by the area of the basin and multiplying by 100. http://www.epa.gov/mrlc/nlcd-2001.html, accessed September 2010.

Walker and others (2016)

Dev

DRNAREA

Drainage area of basin.

Area in square miles

GlobalWatershed

Walker and others (2016)

A

FOREST

Percent area covered by forest land.

Percent of basin area

NLCD 2001, grid cells (30m x 30m) contained within the basin classified as deciduous, evergreen, or mixed forest (land-cover classes 41, 42, 43), and dividing by the area of the basin and multiplying by 100. http://www.epa.gov/mrlc/nlcd-2001.html, accessed September 2010.

Determined by georeferencing the precipitation contour images (Huff and Angel, 1992) for each recurrence interval to a coverage with known spatial reference and digitizing the contour lines, using the Topo to Raster tool from the ESRI ArcMap 9.3 3D Spatial Analyst Toolbox to interpolate to a raster, and calculating the mean of each basin using zonal statistics. For small basins that were unable to be automatically calculated, values were estimated manually.

Determined by georeferencing the precipitation contour images (Huff and Angel, 1992) for each recurrence interval to a coverage with known spatial reference and digitizing the contour lines, using the Topo to Raster tool from the ESRI ArcMap 9.3 3D Spatial Analyst Toolbox to interpolate to a raster, and calculating the mean of each basin using zonal statistics. For small basins that were unable to be automatically calculated, values were estimated manually.

Determined by georeferencing the precipitation contour images (Huff and Angel, 1992) for each recurrence interval to a coverage with known spatial reference and digitizing the contour lines, using the Topo to Raster tool from the ESRI ArcMap 9.3 3D Spatial Analyst Toolbox to interpolate to a raster, and calculating the mean of each basin using zonal statistics. For small basins that were unable to be automatically calculated, values were estimated manually.

Determined by georeferencing the precipitation contour images (Huff and Angel, 1992) for each recurrence interval to a coverage with known spatial reference and digitizing the contour lines, using the Topo to Raster tool from the ESRI ArcMap 9.3 3D Spatial Analyst Toolbox to interpolate to a raster, and calculating the mean of each basin using zonal statistics. For small basins that were unable to be automatically calculated, values were estimated manually.

Determined by georeferencing the precipitation contour images (Huff and Angel, 1992) for each recurrence interval to a coverage with known spatial reference and digitizing the contour lines, using the Topo to Raster tool from the ESRI ArcMap 9.3 3D Spatial Analyst Toolbox to interpolate to a raster, and calculating the mean of each basin using zonal statistics. For small basins that were unable to be automatically calculated, values were estimated manually.

Determined by georeferencing the precipitation contour images (Huff and Angel, 1992) for each recurrence interval to a coverage with known spatial reference and digitizing the contour lines, using the Topo to Raster tool from the ESRI ArcMap 9.3 3D Spatial Analyst Toolbox to interpolate to a raster, and calculating the mean of each basin using zonal statistics. For small basins that were unable to be automatically calculated, values were estimated manually.

Walker and others (2016)

not used

LC01CRPHAY

Percent area covered by Pasture or cultivated Crops from NLCD2001

Percent of basin area

NLCD 2001, grid cells (30m x 30m) contained within the basin classified as herbaceous vegetation that has been planted or is intensively managed for the production of food, feed, or fiber; or is maintained in developed settings for specific purposes (land-cover classes 81, 82), and dividing by the area of the basin and multiplying by 100. http://www.epa.gov/mrlc/nlcd-2001.html, accessed September 2010.

Walker and others (2016)

not used

LC01HERB

Percent area covered by grassland from NLCD2001

Percent of basin area

NLCD 2001, grid cells (30m x 30m) contained within the basin dominated by grammanoid or herbaceous vegetation (land-cover class 71) and dividing by the area of the basin and multiplying by 100. http://www.epa.gov/mrlc/nlcd-2001.html, accessed September 2010.

Walker and others (2016)

not used

LC01WATER

Percent area covered by open water. Does not include wetlands

Percent of basin area

NLCD 2001, grid cells (30m x 30m) contained within the basin classified as open water (land-cover classes 11) and dividing by the area of the basin and multiplying by 100. http://www.epa.gov/mrlc/nlcd-2001.html, accessed September 2010.

Walker and others (2016)

W

LC01EMWET

Percent area covered by emergent wetlands.

Percent of basin area

NLCD 2001, grid cells (30m x 30m) contained within the basin classified as areas where perennial herbaceous vegetation accounts for greater than 80 percent of vegetative cover and the soil or substrate is periodically saturated with or covered with water (land-cover classes 95), and dividing by the area of the basin and multiplying by 100. http://www.epa.gov/mrlc/nlcd-2001.html, accessed September 2010.

Walker and others (2016)

not used

LC01WDWET

Percent area covered by woody wetlands.

Percent of basin area

NLCD 2001, grid cells (30m x 30m) contained within the basin classified as areas where forest or shrub land vegetation accounts for greater than 20 percent of vegetative cover and the soil or substrate is periodically saturated with or covered with water (land-cover classes 90), and dividing by the area of the basin and multiplying by 100. http://www.epa.gov/mrlc/nlcd-2001.html, accessed September 2010.

Walker and others (2016)

not used

PRECIP

1971–2000 mean annual precipitation in the basin, in inches.

Area-weighted mean

Interpolating point precipitation data to a raster format with 30m x 30m grids and using ordinary kriging with linear semivariogram (tool contained within ArcGIS 10.1). Calculating the mean of each basin using zonal statistics.

Walker and others (2016)

not used

SNOFALL

1971–2000 mean annual snowfall in the basin, in inches.

Area-weighted mean

Interpolating point snowfall data to a raster format with 30m x 30m grids and using ordinary kriging with linear semivariogram (tool contained within ArcGIS 10.1). Calculating the mean of each basin using zonal statistics.

Walker and others (2016)

not used

SOILPERM

Mean Saturated hydraulic conductivity (Ksat) in the basin. Ksat is the ease in which water can move through a medium (in/hr).

Area-weighted mean

Extracted Ksat data from SSURGO datasets for each county using U.S. Department of Agriculture Soil Data Viewer software (http://soils.usda.gov/sdv/) with the following rating options: Aggregation method = weighted average, Tie Break Rule = fastest, Layer Options = surface layer, merging the data into a statewide map, creating a raster from the statewide data using a cell size of 30 m, and calculating the mean of each basin using the Zonal Statistics geoprocessing tool located within Spatial Analyst in ArcGIS 10.1. The computed value, in micrometers per second, was then converted to inches per hour.

Walker and others (2016)

Ksat

WETLAND

Percent area covered by wetlands.

Percent of basin area

NLCD 2001, grid cells (30m x 30m) contained within the basin classified as areas where forest or shrub land vegetation accounts for greater than 20 percent of vegetative cover, where perennial herbaceous vegetation accounts for greater than 80 percent of vegetative cover, and the soil or substrate is periodically saturated with or covered with water (land-cover classes 90,95), and dividing by the area of the basin and multiplying by 100. http://www.epa.gov/mrlc/nlcd-2001.html, accessed September 2010.